Coolant Pressure Tester

[fixedgear]

What model of Coolant Tester do you people recommend, and is it a worthwhile purchase, or is it one of those infrequently used items that you usually leave to the local VW service shops. Bentley chapter 19 mentions Stant ST-255 A, or AC-PCT3. Is there a current affordable version that will work on the mouth of the expansion tank, and possibly also chenck the cap as well (will be replacing, but it would be nice to have this feature.) Thanks, Chris

[mightyart]

I use a wind sock, but I bet you have a waterboxer so you need a real one.
Myself I wouldn't spend the money on one, I'd pay someone to check it if I thought there was a problem, but of course it is getting harder and harder to find someone that can do a correct test on Vanagons

[fixedgear]

[Wildthings]

I have one, don't use it often, but like having it for those times a leak is hard to pin point. Cost less then missing a couple of hours of work while concurrently having to pay someone else to do the pressure check.

[fixedgear]

[Wildthings]

Without actually going out a looking at it I think mine is a Stant. I have had it for quite a few years now so I do not remember what I paid for it. I remember that I paid much less than list for it though and did pay extra to get the adapter to fit the VW pressure tank and cap.

You might try eBay or just do an internet search. Somewhere someone must sell them at a deep discount. Amazon.com doesn't look to bad for the basic unit.

http://www.amazon.com/Stant-12270-Radiator-Pressure-Tester/dp/B0002SRGWU

[wbx]

I rolled my own. I took an old blue cap, gutted it with a modest application of brute force and ignorance, hooked up a hose and a bike pump, and pumped away.

Unfortunately, it didn't tell me anything (system held pressure over several hours). Anyway, just an option...

-Damon
_________________
'84 Westy (first owner).......but my daily driver has pedals
My "perspective" mantra:
A Volkswagen Vanagon is just a material thing,
As such, it is of the earth,
And if i need to, I can let my Van go.

[tencentlife]

Good idea, Damon. You can also just remove the reserve tank hose from the existing cap, and pump air into it thru the nipple as a way to force leaks. You don't get a pressure reading to monitor that way, but if it sits overnight and there's still pressure, and no leaks are visible, that's a pretty good test without buying a tester.

I wouldn't bother testing a cap anyway; new ones are twelve whole dollars, and you should replace it every 4 years along with the thermostat whatever else you do.

Nice to have the proper tester, though, and if you need a test, it doesn't do much good to have a shop do it once, unless the system happens to be perfect, in which case there wouldn't be a problem and you wouldn't even be there. If there is a leak, you end up having to do it again and again, as you fix things, until it holds. That's a lot of shop time, and would quickly pay for your own tester.

[fixedgear]

Thanks Damon and TenCentlife. Going the bike pump method may work for me of the following items are not going to fit the bill:

http://www.matcotools.com/Catalog/toolcatalog.jsp?cattype=T&select=&cat=2153
I will have to get to Matco to see if $47.55 is the total tool price. It seems too low since the generic tester in the section before is in the $155 category.
I got the lind from the vanagon.com site, where the author mentions a fill and bleed procedure the does not require running the engine. He uses the following spill free funnel to get the coolant to a height above the bleed hole. Still raises the front 15" or so to attain a height for the bleed hole in the rad above the height of the rest of the system. My question is: Is not the bleed hole the highest point already, why the necessity of raising the front?
http://www.matcotools.com/Catalog/toolcatalog.jsp?cattype=T&cat=2270&page=1&
I would like to dump the coolant, flush and refill and bleed the system, around the same time that I change the fuel lines and filter. If the tool cost is as quoted, I think I can justify the cost.
Thanks again, Chris

[tencentlife]

The radiator bleed opening is already the highest point in the system by far, it's true. But the coolant lines do not have a consistent upward slope, so air can be trapped there. That is why you should elevate the front of the van.

With the standard method, it is also important to raise the rpms to 2000 and fill from the rear, at the expansion tank, while the engine is cold. The higher revs allow the pump to develop better static head, as the system is open to air (an impeller pump has very little static head in an open system, but delivers good dynamic head in a closed loop, which the system becomes once it is filled and sealed).

If the thermostat is at all open, as the fluid is lifted to the radiator, filling it from the bottom, the pump suction will be pulling the fluid back to the motor down the return pipe, and the entire radiator won't get filled to the top. When the T-stat is closed, the return pipe is effectively blocked, and the pump will fill the radiator from the bottom up, fluid will pour back down into the blocked return line, also filling it from the top, displacing the air in the line, and when the return line is filled, the pump will proceed to fill the rad from the bottom to the top, when fluid will finally gush out of the air hole. That is why it is important to fill while the motor is still cold.

If you want to avoid running the engine while filling, for whatever reasons, you could fill the motor thru the expansion tank on level ground, let it settle to allow air bubbles to detach and rise, until the tank will admit no more fluid. Then seal the tank and elevate the front. You could then fill the radiator from the top air hole, but it would be a very slow process, and wouldn't guarantee getting all the air out as well as the standard method does.

Using a tall sealing funnel accomplishes what the standard method does, by creating a fluid column high enough that the static head is equal to the height of the radiator top. But to allow all the air to rise out of the long pipes without being trapped, you would still want to elevate the front, so the funnel column would need to be that much taller.

Overall, the standard method is the least work, in my opinion, and works reliably if you do it correctly. Several things are important to note:

Fill the engine first on level ground, and allow time for air to separate within the head passages. When the fluid level in the expansion tank no longer falls after a time, then cap the expansion tank and raise the front. This way, the water jackets are holding a minimum of air bubbles, and you will avoid spot boiling that will disrupt flow.

Use premixed coolant.

Fill with engine cold.

Raise rpms to 2000 by shimming the throttle stop.

Open the expansion tank as soon as the motor is running, and add coolant as fast as it will take it, never letting the tank get empty.

Make sure coolant is gushing from the radiator top in a clear stream. Seal the airhole as soon as it does. Then fill and cap the expansion tank and shut the motor off. Level the car, and run until warm, making sure there is always fluid in the expansion tank.

Finish by reconnecting the overflow tank and filling it to the Max mark. Note the changes in level here for the first week of running, keeping it between the marks.

[fixedgear]

Thanks for the detailed reply Tencentlife.
What got me focused on the non-running bleed method was this:

Addendum, written several days later:

The problem these tools and procedure address is the need for the bleeder
hole in the radiator to be the highest point in the system so that bubbles,
hopefully all of them will rise there and escape, is compounded by the filler
being lower than the bleeder making the coolant naturally flow out of the
filler. So VW came up with that ridiculous solution you read in the manuals of
running the engine and therefore the pump to force the coolant forward and up.
This long funnel procedure accomplishes the same without running the engine,
needing an assistant, and all the attendant heat,noise and spill mess.
Any solution you can devise hardware wise that extends the filler higher
than the bleeder while the bleeder remains higher than any other part of the
cooling system will accomplish the same. I included the URLs to the funnel and
pressure tester adapter to show the tools helpful to anyone doing this work on a
regular basis.
Frankly, I strongly recommend that anyone owning a Vanagon and self
servicing it own a standard Stant brand pressure tester set, or equivalent,
along with the adaptors for both the bottle threads and for the cap. As a
professional, all major services on all liquid cooled vehicles get a thorough
cooling system test, the pressure test being the most fundamental along with
hydrometer readings. I haven't used one yet, but I hear the refractometers are
even better, certainly they are far more expensive. Recommended best procedure
would be to change the coolant annually, please be responsible and recycle
appropriately.
Seems that if one could raise the front to the height that would get the
bleeder and filler EXACTLY the same height might work well too, but it would be
a lot of work to measure out unless you had a perfectly level work surface.

Prior to picking up the vanagon, the PO had told me that the temp. guage did not work. He mentioned that he would work on it though, and on pickup confirmed that it did work. In 2200 miles of return trip however, the guage never got above about 7 or 8 o'clock on the guage (got to about the top of the white swoosh stripe on the bottom left.) The expansion tank was full, but the overflow was empty or very low, prior to the journey. Filled up with 50/50 VW coolant to max mark on the overflow and the level stayed fairly constant until parked in Manitoba for the winter. Checking the coolant rating with a hydrometer indicated protection only to -18 or so, so I thought it was best to not attempt to start over the storage period; put in stabalizer, filled tank, changed oil, and that is about it. The level in the overflow was slightly above the min. mark while hibernating.

I thought that the lack of heat from the vents might signify cooling issues, but the dash vent facing the passenger was broken, and was letting in full time outside air, so I came to the conclusion that I would await early spring and do a full system flush and refill, change the thermostat, and go from there.

I cannot phone connect to check on the price of the kit plus necessary adapters, but I assume the price is only for adapters for the top of the expansion bottle and possibly the cap. Thanks again, chris.
Your method looks like I could do it on my own-and I am not sure why the author recommends the non-running method instead.
Chris

[Volksaholic]

Hey TenCent... great writeup! I'm new to Vanagons, having driven mostly aircooled cars and a smattering of conventional water cooled cars over the last 30+ years. I have never seen such a convoluted coolant fill configuration, but I went with the Bentley method when I was done replacing heater cores and it seemed to work well. Getting the front of the van up 15" ( I think that's what Bentley calls for) is not a trivial matter though... luckily my driveway has a pretty good slope to it so I can park uphill and use the jack & jack stands from there (BLOCK THE REAR WHEELS WELL!).

I do have a couple of questions for you all, though:

1. Is the bleeder screw on the radiator supposed to be a bolt or a fitting with a hose connector? Mine is a bolt but somewhere I saw a picture of a hose connector version (like a brake bleeder valve on steroids) and that would sure be preferable to trying to catch the overflow without a hose.

2. Is there a good way to test heater cores? In the process of getting the front and rear heaters going I bought a couple of spares that seem clean. I really bought them for the blower motors, but if the cores are good I want to save them because... well.. the new ones are damned expensive! I thought about pressurizing the cores to about 12 psi (that's about right, isn't it) and then just looking for it to leak down or holding it under water like a bike tire. Any other suggestions?

[tencentlife]

I'm not going to discuss the non-running fill method, not because I have an opinion about its relative value so much as that the basic principles of a water level are pretty obvious to anybody and it is taking advantage of that property. To each his own.

I just prefer the standard method, because I've done it singlehandedly numerous times and have never found it any trouble, and never have had problems with my cooling system, either. I just followed the procedure rote (except for the 15" raise; seems like 10-12" is enough), and it was only much later that I thought about it and figured out why it works as it does. To do that I first had to understand how this cooling system works. I'm not surprised that it perplexes many folks, but once I realised how and when and where fluid flows in the system, it all made sense, and I actually think it's pretty brilliant how the engineers dealt with the problem. They made their mistakes on the 1.9, which is why the 2.1 got partly redesigned. I'm gonna hear from those that think the 1.9 is better for some reason or other, mostly because you like what you know, but to me the later system is clearly superior, particularly for the very clever way it purges air while running.